论文部分内容阅读
目的探讨在炎症情况下,瘦素(leptin)对胰岛β细胞胰岛素合成与葡萄糖刺激的胰岛素分泌(glucose-stimulated insulin secretion,GSIS)功能的影响。方法在含5.5 mmol/L葡萄糖培养基中培养传代的大鼠胰腺癌细胞系(INS-1E)和大鼠原代分离的胰岛,经生理浓度leptin(0.5 nmol/L)或TNF-α(2 ng/ml)及高浓度leptin(10 nmol/L)与TNF-α(20 ng/ml)单独及联合处理48 h后,在基础葡萄糖(3.3 mmol/L)或高糖(16.7 mmol/L)中分别刺激1 h,放免法检测葡萄糖刺激的GSIS功能;用RT-PCR方法检测胰岛素原(proinsulin)mRNA表达水平,同时细胞经超声破胞后检测胞内胰岛素含量。结果高浓度leptin(10 nmol/L)或TNF-α(20 ng/ml)单独刺激组与对照组以及低浓度leptin或TNF-α组相比,均可显著性抑制INS-1E细胞和原代胰岛的GSIS功能(P<0.05),与之相应的是细胞内proinsulin mRNA水平以及胞内胰岛素含量亦显著降低(P<0.01);但TNF-α+leptin联合刺激组中,胰岛素原mRNA水平及胰岛素蛋白含量均较leptin单独刺激并未进一步降低,反而有显著升高(P<0.05),提示TNF-α具有拮抗leptin抑制胰岛素基因表达和分泌的作用。结论 TNF-α可以干扰leptin对胰岛β细胞胰岛素合成和分泌的抑制作用。提示肥胖者体内升高的TNF-α可能通过拮抗leptin对胰岛素分泌的抑制作用,在肥胖伴随的高胰岛素血症的发生及葡萄糖代谢紊乱中具有重要作用。
Objective To investigate the effect of leptin on the insulin synthesis and glucose-stimulated insulin secretion (GSIS) in pancreatic islet β cells under inflammatory conditions. Methods The rat primary pancreatic cancer cell line (INS-1E) and rat primary isolated islets were cultured in 5.5 mmol / L glucose medium. The cells were cultured in the presence of physiological concentrations of leptin (0.5 nmol / L) or TNF-α After treatment with basic glucose (3.3 mmol / L) or high glucose (16.7 mmol / L) for 48 h, the cells were treated with 20 ng / ml leptin (10 ng / And stimulated by glucose for 1 h respectively. Glucose-stimulated GSIS function was detected by radioimmunoassay. The expression of proinsulin mRNA was detected by RT-PCR, and the intracellular insulin content was detected by cytopathic effect. Results Compared with the control group and low concentration of leptin or TNF-α group, the concentration of leptin (10 nmol / L) or TNF-α alone (20 ng / ml) GSIS function of islets (P <0.05), correspondingly, the level of intracellular proinsulin mRNA and intracellular insulin content also decreased significantly (P <0.01). However, the levels of proinsulin mRNA in TNF-α + leptin combined with stimulation group Compared with leptin alone, insulin level did not decrease further, but increased significantly (P <0.05), suggesting that TNF-α antagonizes the effect of leptin on insulin gene expression and secretion. Conclusion TNF-α can interfere with the inhibitory effect of leptin on insulin synthesis and secretion in pancreatic β cells. It is suggested that elevated TNF-α in obese people may play an important role in the occurrence of hyperinsulinemia accompanied with obesity and glucose metabolism disorders by antagonizing the inhibitory effect of leptin on insulin secretion.